The 10-Coin Hex is a type of Hex in Mario Party DS. The player who possesses it can choose to place it on any Blue Space or Red Space within five spaces from their current location. Then, if an opponent lands on it, 10 coins will be taken from them. If the player who threw it lands on it, the hex will be cancelled out, but he or she will receive 5 coins.
Trivia
The 10-coin Hex will flatten you by falling on you in a manner that reminds of the carnivorous plants appearing on the Wiggler Garden board.